An in-vehicle electric apparatus such as an in-vehicle navigation apparatus includes, in general, a flash memory as a general memory. For example, JP-A-H09-182010 corresponding to U.S. Pat. No. 6,067,398 teaches such an apparatus. This type of the flash memory includes an IPL (i.e., initial program loader), a flash memory for storing an OS (i.e., operating system) and an application program, and a flash memory card for a map medium. The flash memory for the boot device is a NOR type flash memory. Therefore, dimensions of the memory are large, and a manufacturing cost is high. On the other hand, the flash memory card for the map medium is a NAND type flash memory, and therefore, dimensions of the memory are small, and a manufacturing cost is low, and further, a memory capacity is large. Thus, when the NAND type flash memory is used for the boot device, the manufacturing cost is reduced.
The NAND type flash memory includes an inherent failure block in multiple memory blocks, which provide the flash memory. Further, when the flash memory functions, a new failure block is generated. Thus, the memory card controller controls the flash memory not to use such a failure block. Further, the NAND type flash memory has the limitation of the number of rewritable times. The memory card controller also manages the number of rewritable times of the flash memory.
In the NAND type flash memory such as a SD card, in order to manage the number of rewritable times and the failure blocks, the memory card controller executes an initialization setting process when a power source energizes a system, i.e., when an accessory switch turns on. Here, in the initialization setting process, the memory card controller searches (scans) all of the flash memories, and the memory card controller searches or scans conversion tables stored in the flash memories. The memory card controller spends about one second at maximum for completing the initialization setting process. This is obtained by actual measurement results. Accordingly, when the SD card is used for the boot device, for example, the CPU can not access the flash memory while the memory card controller executes the initialization setting process. As a result, a reading process of the CPU for reading an IPL initially from the flash memory is delayed. Thus, the activation of a soft ware such as an OS is also delayed, so that a response of communication to an in-vehicle LAN may not be on time.
Thus, even when the accessory switch is off, but a backup power source connecting to the battery is coupled with the SD card so that the initialization setting process is only performed in a manufacturing process of the system after the system is energized. Thus, the initialization setting process of the SD card is not performed under a condition that an user utilizes a vehicle, which mounts the system.
The CPU controls the SD card to store backup data therein when the accessory switch turns off. When the CPU can not control the SD card to backup the data normally, it is necessary to reset the SD card since the backup process of the SD card is not completed normally.
However, when the system includes the above features, it is necessary to initialize the SD card when the accessory switch turns on. Thus, when the SD card is initialized, the initialization setting process is executed in the SD card. Thus, the activation of the soft ware is delayed.